so...why am I nervous?

Tonight is the night. I have been asked to sub for a teacher who is out of town. up until a month ago, I have been the only show in town and now the big gym with money just oooooozing out of their pockets opened up a very pretty 20-bike indoor cycling studio. I have asked them to stop calling it spinning and they have assured me that they will in the next printing, so I don't have to go all legal on them - I don't want a hostile relationship with them...I HOPE they do become an official studio with a trained instructors, etc.
anyway, I went in yesterday to get the lo-down on the lights/a.c/mic etc etc and the guy spent 20 minutes (I couldn't distract him!) showing me how to use the disco ball and strobe lights! You can PROGRAM them...as you teach....red, if you want them to be out of their minds...
oh my goodness....I want them to be IN their minds...and I just didn't have the time to do anything else but ask how to use the small white track lights.
so....why am I so nervous? I am doing what I do best on this planet...but am I going to meet with people who want to disco???
exhale....I'll repost on this thread....tomorrow...
...subbing can be so difficult - but my husband is coaching me: "just go do your thing...they'll love you or hate you, but you have full classes every other night in your own studio, so just go have fun." hoping that is possible!
c